Operation Yellow Ribbon was commenced by Canada to handle the diversion of civilian airline flights in response to the September 11 attacks in 2001. Canada’s goal was to ensure that potentially destructive air traffic be removed from United States airspace as quickly as possible, and away from potential U.S. targets, and instead place these aircraft on the ground in Canada, mostly at military and civilian airports in the Canadian provinces of Nova Scotia, Newfoundland and Labrador, and British Columbia (and also several in New Brunswick, Alberta, Manitoba, Ontario and Quebec) where their destructive potential could be better contained and neutralized. As none of the aircraft proved to be a threat, Canada and Canadians subsequently undertook to play host to the many people aboard the aircraft during the ensuing delay in reaching their destinations.

Operation Yellow Ribbon had many consequences for Canadians. After the initial task of diverting the flights was over, thousands of stranded passengers and flight crews had to be housed and fed until the crisis was over. During the diversion of flights, some airports, including Vancouver International, were inundated with hundreds of telephone calls from members of the public and the corporate community offering their support. In Ottawa, SitCen staff were also inundated with calls from airports, air carriers, the media, and the general public. On average, SitCen staff received an estimated 5,000 calls a day.